How to go from zero to Half-Ironman-ready in 6 months

From January 1 to 70.3: Here's how you can complete a half-Ironman in six months—and make your most audacious New Year’s resolution a reality.

by Robert Bergland

Paul Bradbury/Getty Images

So, you’ve eaten way too many of Grandma Irene’s Christmas cookies and skipped the gym a few too many times in December. You’re afraid the talking scale you got for Christmas will start calling you “Lard Ass”.

A 5K? Lame. The full 26.2 marathon? Getting warm. But for something really Facebook-worthy that doesn’t require quite so much running (and that your brother-in-law Steve hasn't already done), try a different number: 70.3. Of course, on Facebook you’ll post that goal by its other name: Half-Ironman.

For the man who wants to really turn his fitness around, the half-Ironman triathlon is the Goldilocks distance, the “just right” balance of multi-sport training that's challenging, doable before autumn, and not as insane as the full Ironman. (Save that for 2019.)

The 70.3 figure is the number of miles you will travel: 1.2 miles in the water, 56 miles on the bike, and a half-marathon (13.1 miles) on your own two feet. While that may seem like a helluva lot to reckon with in January, with hard work and daily commitment, it’s a goal that is very attainable, says Gale Bernhardt, an elite-level triathlon coach and author of Triathlon Training Basics.

“I think literally anyone can [do it]," Bernhardt says. “A person can go from zero to an Olympic distance [.9-mile swim, 24.8-mile bike, 6.2-mile run] in about 12 weeks. You need only about an 8-10 week bump on top of that to get to a half-Ironman. It’s a pretty achievable goal.”

Don’t believer her? Talk to Marcus Cook, who went from weighing 489lbs to completing both a half-Ironman and a full Ironman in fewer than 20 months.

You're not the only person considering a half-Ironman, either. Since the inaugural Ironman-branded 70.3 race in 2001, the sport has grown steadily, and there are now 100 races. There are many other nonbranded 70.3 races sanctioned by USA Triathlon (USAT), such as the Illinois Route 66 Triathlon started in 2013 by Steve O’Connor and Tri Harder Promotions, in response to athlete requests for a longer race.

“People will start with the sprint and then go to an Olympic, and then the half is the next step,” O’Connor says. “A lot of people will just stop at the half, because the full is such a big time commitment.”

USAT Communications Manager Caryn Maconi agrees: “It’s much more accessible than a full Ironman. It doesn’t require giving up your life and free time like the Ironman does. A lot of people start with the sprint and Olympic and move up, seeing the half-Ironman as the next step in that challenge.”

1. Find a good race

In addition to the Ironman.com website, two other good sites on which to find triathlons aretrifind.com and active.com.

“For your first race, pick a course that isn’t the hardest or hilliest one around,” Bernhardt says. “You want to set yourself up for success.”

2. Take it easy at first—and build in recovery time

Follow the 10% rule: Try not to increase your training mileage more than roughly 10% each week, O’Connor suggests. “Everyone wants to do too much too fast. Don’t overdo it. That’s the risk with the half-Ironman people—they tend to be overzealous.”

Bernhardt advocates having some weeks that increase mileage a little bit more than 10%. At the same time, you should insert recovery days and recovery weeks to avoid potential injury. Her ideal training week for beginner triathletes involves fewer than three hours of total training:

By the fourth week of her beginning training plan (she has several plans on her website), you should be able to put those legs together for a sprint triathlon (usually around a 500-yard swim, 15-mile bike, and a 5K). From there, the training involves both building up distances and having a recovery week every few weeks, in which you'll reduce your distances by about 50%. The longest week of training is only about 6.5-7.5 hours total, with individual workouts that approximate the half-Ironman legs, outside of an extra-long swim workout to boost confidence in the water.

3. Do a few open-water swims

Training outside of the clear, pristine pool lanes, where you turn around every 25 yards, is also critical for confidence.

“The swim’s a big concern for everybody,” O’Connor says. “You can train in the pool all you want, but you really need that exposure to the open water.”

4. Do a sprint and/or Olympic-distance triathlon first

Both O’Conner and Bernhardt strongly advise doing a shorter triathlon first, because it will grant you open-water experience and practice for the logistics and transitions of the half-Ironman. Getting used to setting up your transition area, changing shoes and equipment and handling nutrition can help you avoid mistakes for the half-Ironman.

5. Know your nutrition needs

When you’re sweating quarts and burning through a couple thousand calories a day, your fluid and caloric intake is critical. But don't assume you need to carb-load like old-school marathoners did, says Bernhardt, co-author of The Fat Burning Machine. A better option is to try a variation of the keto diet: Bernhardt shuns carb-rich diets and instead trains the body to burn fat, reducing race-day calorie intake to 100 calories/hour and, in doing so, reducing stomach problems many carb-gorging triathletes encounter.

6. Get good equipment—but don’t go overboard

With the miles you’ll be doing, you’ll want to have good running shoes and more than just a garage-sale 10-speed. But, don’t feel the need to drop thousands of dollars on top-of-the-line cycling equipment just yet. “It’s not about the equipment,” Bernhardt says. “When you get really fit, it makes a difference, but when you’re a beginner, I’m not sure how much it buys you.” In many cases, losing a few pounds off that lard ass makes more sense than shelling out big bucks for a slightly lighter all-carbon-fiber bike. Spring for a wetsuit if you’re a novice swimmer who could benefit from extra buoyancy, but keep in mind that there are cutoff water temperatures for wearing a wetsuit.

7. Have fun

Yes, some days will require a lot of willpower to get out there and put in the miles you need. But in your training and on race day, be sure to have fun and enjoy the ride. If you do, who knows? Maybe in 2019 you'll get an Ironman logo tattooed on the back of your calf.